[LAD] RT

[Dominique Michel]

Le Fri, 25 Apr 2008 12:35:43 -0400,
"Joshua D. Boyd" <jdboyd at jdboyd.net> a écrit :

> Is it possible to configure a system (included changes to programs) so
> that nothing can interfere with a few RT threads?
> 
> I have an audio and video thread in a program, and they are running as
> SCHED_FIFO, but so many things can interfere with those two threads,
> such as USB plugs/unplugs, cron log rotations, disk access (PIO flash
> disk), ssh logins, etc.  I really would like to shore up performance
> here.
> 
> I am not using Ingo's RT patches, but I still see people talking about
> turning off things like cron and server processes to prevent xruns when
> using Ingo's RT patches.  While I have turned off cron, turning off sshd
> and the web server aren't options.  I want to instead somehow make sure
> that neither can every interfere with the AV threads, even if  it means
> that SSH and web traffic are extremely slow.
> 

http://proaudio.tuxfamily.org/wiki/index.php?title=Realtime_%28RT%29_Kernel#IRQ_tweaking

You must use the rtirq package. It is a boot script that use chrt to fix the
priorities for different IRQ. The trick is to setup the highest priority to the
rtc (the system will hang otherwise), followed by the sound, followed by the
other pieces of hardware.

If your distribution doesn't provide this package: http://www.rncbc.org/jack/

Cheers,
Dominique